Iran's military fired at least two missiles at commercial ships transiting the Strait of Hormuz on Monday night, two U.S. officials tell Axios.The IRGC attacked a third commercial ship on Tuesday morning, a U.S. official said.Why it matters: The reported attacks threaten to unravel a memorandum of understanding signed less than three weeks ago under which Iran agreed to halt attacks in the Strait of Hormuz.And they come after a one-week agreement between the U.S. and Iran on halting attacks in the strait expired.The U.S. is likely to retaliate with strikes against Iranian targets. Driving the news: The United Kingdom Maritime Trade Operations said Monday that it had received a report from a tanker traveling south near Oman along the Strait of Hormuz coast that had been struck by an unknown projectile, causing a fire.A U.S. official said a second commercial vessel had been struck by an Iranian missile.Both vessels suffered significant damage but no casualties, the U.S. official said. State of play: A round of indirect talks between the U.S. and Iran in Doha, Qatar, last week ended without much progress on the issue of the Strait of Hormuz.